Definition of Takayasu arteritis:

Takayasu arteritis is an inflammation of the aorta -- the artery that carries blood from the heart to the rest of the body -- and its major branches.

Causes, incidence, and risk factors:

The cause of Takayasu arteritis is unknown. The disease occurs mainly in children and women younger than 30, especially those who are of Asian or African descent.

It appears to be an autoimmune condition, where immune cells are wrongly targeted against the body's own tissues, and it may involve other systems.